1. Field of the Invention
This invention relates to the use of special carbonic acid esters as foam control agents in the processing and/or production of foods and in fermentation processes.
2. Discussion of Related Art
Foam problems can be prevented before the formation of foam by addition of foam inhibitors and after the formation of foam by addition of defoamers. In this sense, both foam inhibitors and defoamers are foam control agents.
In the industrial processing and/or production of foods, considerable significance is attributed to the control and prevention of foaming. For example, in the industrial processing of sugar-containing plant juices, as carried out on an industrial scale in the case of sugar beet, particular difficulties are caused by excessive foaming in the diffusors, in the defecation units, in the carbonizing tanks and in the evaporators. It is also important in the production of potato products, such as chips or pommes frites (French fries), in the production of baker's yeast using molasses or other industrial fermentation processes, such as the production of medicaments, to reduce foaming to a level which does not interfere with the industrial production process.
The auxiliaries used to regulate foaming in the sugar industry could enter the end product, sugar, in traces, so that physiologically completely safe foam control agents are of course essential. In addition, foam control agents which enter the wastewater during the external beet washing process should be readily bioldegradable. Moreover, the potential residues of foam control agents, which enter the molasses during processing of sugar beet, should not adversely affect yeast production because the molasses thus obtained is used as a nutrient in the industrial production of baker's yeast. Where they are used in the potato-processing industry, foam control agents must be at least capable of regulating the starch foam which is so difficult to control. In practice, foam-suppressing agents are generally expected to develop a good spontaneous effect and to show a good long-term effect in low concentrations.
Fats and oils, such as rapeseed oil, peanut oil, olive oil and wool grease, have long been used for defoaming in the sugar and yeast industries. Fatty acid monoglycerides, fatty acid polyglycol esters, polyalkylene glycols, ethylene oxide adducts with alkyl phosphoric acids and with branched alcohols, alkylene oxide adducts with oligosaccharides and free fatty alcohols have also been proposed for this purpose. Typical foam control agents with patent literature references and potential applications are described in Ullmanns Enzyklopadie der technischen Chemie, Vol. A 11 (5th Edition) 1988, pages 465 to 490.
According to DE-AS 12 42 569, carbonic acid esters in which the alkyl groups may optionally be interrupted by an oxygen atom are used as foam-suppressing agents for foaming detergent systems containing anionic, cationic and nonionic compounds. The machine washing and disinfection of bottles and cans in the food industry is mentioned as one possible application. Although the dialkyl carbonates mentioned in the cited document have a good defoaming effect for this particular application, this does not necessarily mean that they are suitable for other applications, including for example the sugar industry, the potato industry and fermentation processes and their special requirements. Thus, in the sugar industry for example, totally different substances, such as saponins, are responsible for foaming and, accordingly, also influence the constitution of the foam generated. In addition, bottle washing processes differ considerably in their mechanics and, above all, in the introduction of air which in turn impairs the nature and extent and the foam formed.
U.S. Pat. No. 3,332,980 describes alkoxylated carbonic acid esters of which the alkyl radicals have a degree of alkoxylation of 1 to 150 and which may be used for various applications. One of the many possible applications of these substances includes defoaming in its broadest sense, although the document in question does not mention which of the alkoxylated carbonic acid esters may be used in which quantities for which type of defoaming. As explained, however, foams often differ considerably from one another, so that there was still a need for special compounds which would satisfy the above-mentioned requirements for use as a foam control agent in the sugar industry, in the potato-processing industry and/or in fermentation processes.
Accordingly, the problem addressed by the present invention was to provide new special foam control agents which would show improved spontaneous and long-term activity in low concentrations and which in addition would satisfy the requirements for their use in the sugar industry, in the potato industry and in fermentation processes.